Semiconductor image sensors are used to sense radiation such as light. Complementary metal-oxide-semiconductor (CMOS) image sensors (CIS) and charge-coupled device (CCD) sensors are widely used in various applications such as digital still camera or mobile phone camera applications. These devices utilize an array of pixels in a substrate, including photodiodes and transistors, that can absorb radiation projected toward the substrate and convert the sensed radiation into electrical signals.
A back side illuminated (BSI) image sensor device is one type of image sensor device. These BSI image sensor devices are operable to detect light projected from the backside. The BSI image sensor devices include color filters for filtering a specific wavelength band of the incoming light, which corresponds to a color in a color spectrum. However, conventional methods of forming color filters for BSI image sensor devices have been prone to suffer from thermal expansion issues, particular in a scribe line region of the BSI image sensor device. Such thermal expansion may cause lateral stress to a photo-sensitive region of the image sensor and degrade dark current performance of the image sensor.
Therefore, while existing semiconductor image sensors have been generally adequate for their intended purposes, they are not entirely satisfactory in every aspect.